Ball set back detent



July 24, 1962 c. F. BROWN ETAL 3,045,598

BALL SET BACK DETENT 2 Sheets-Sheet 2 Filed Jan. 12

FIG.4.

FIG.5.

INVENTOR5. C. F. BROWN R. M.JAOKSON R. T. CAMPBELL A RNEYS,

United States Patent Ofifice 3,045,598 Patented July 24, 1962 BALL SETBACK DETENT Calvin F. Brown, Paradise, and Roderick M. Jackson andRichard T. Campbell, Lancaster, Pa., assignors, by mesne assignments, tothe United States of America as represented by the Secretary of the NavyFiled Jan. 12, 1959, Ser. No. 786,438 6 Claims. (Cl. 10280) Thisinvention relates to a fuze construction for a rotative missile, andmore particularly to the arming of the missile.

In Ordnance missiles having explosive charges, it is desirable that themissile be maintained in a safe or unarmed condition until it has beendischarged or fired and is at a safe distance. Ordinarily a safetydevice designed to be actuated by setback or by centrifugal force isincorporated in the missile. Sometimes a setback mechanism may beprematurely actuated by dropping and a centrifugal force operated deviceby rolling so that an otherwise safe missile is armed when it should notbe. This is undesirable.

The object of the present invention is to provide a new and improvedsafety device for a fuze which needs both a setback force and acentrifugal force to render the missile capable of exploding.

A further object of the present invention is to provide a rotor mountedso as to be subject to setback forces and also subject to thecentrifugal force of the spinning missile and to provide moving partscooperating with the rotor so that it will assume an armed position onlyafter being subjected to set back force and centrifugal force in turn.

It is a still further object of the invention to provide an armingdevice which will operate on being subjected to a setback force andsubsequently to a centrifugal force with a limiting factor that delaysthe action of the centrifugal [force until the acceleration is zero.

It is a still further object of the invention to provide a fuze having asafety arming rotor which is prevented from rotating by a ball, whichball is moved through setback force to a new or second position and isheld in said new position during acceleration of the missile after whichcentrifugal force will cause the ball to again move to a third positionwhich will permit rotation of the rotor to an armed position.

Other objects and many of the attendant advantages of this invent-ionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is a vertical section showing the essential parts of theinvention in safety position;

FIG. 2 is a view similar to FIG. 1 showing the movement of the pants dueto setback force;

FIG. 3 is a view similar to FIGS. 1 and 2 showing the parts at theinstant before arming;

FIG. 4 is a top plan view of the invention with the essential parts insafety position; and

FIG. 5 is a similar view showing the parts in armed position.

Referring particularly to the drawings, certain parts necessary toillustrate the invention are shown and designated by like numeralsthroughout the several views. Other parts closely associated with theparts shown are omitted as they form no part of the invention.

The bottom plate 8 of a switch housing 9 is formed with an oif centerhole having a top [referring to the posi tion shown in the drawings]section 10 slightly larger in diameter than a lower or reduced section12. The lower part of the wall of the reduced section 12 is flared as at14 to accommodate the end of the cup as will be hereinafter described.

A ball retaining cup 16 fits the lower section 12 and is for-med with anannular flange 18 adapted to engage the bottom of the top section 10. Aball 20 is held in the cup 16 by slightly crimping the lower end as at22 [FIG. 1] with the ball projecting below the plate 8. A frictiontitted cap 24 [shown in FIG. 1 only] closes the hole and prevents axialmovement of the cup in the hole.

Separated from the bottom plate 8 by a diaphragm 26 is a rotor housing28 formed with an oif center cylindrical well 3%} in which a rotor 32 islocated. The diaphragm 26 is formed with an arcuate shaped hole 27 whichprovides clearance between the plate 8 and the rotor carried ballpermitting the rotor to turn freely through the of are necessary forarming. A tapered hole 34 depends from the well 30, said hole being inline with the hole formed in the bottom plate of the switch housing.

The rotor 32 has a diametric groove 36 housing a moveable strip 38. Therotor 32 has a notch 40 cut into the circumference to reduce the weightat that point. At a second point approximately 90 from the notch therotor is bored and the hole filled with lead as shown at 41. Thisprovides an unbalanced rotor which when subjected to centrifugal forcewill be sure to rotate through a predetel-mined arc. A groove 42 in thecircumference limits the rotary movement of the rotor by either shoulder44 or 46 engaging the pin 48. When the pin 48 is in engagement with theshoulder 44, the rotor is in a safety position and when in engagementwith the shoulder 46 the rotor is in an armed position. The rotor isalso formed with two holes 50 and 52 substantially in a diametric lineand opposite each other. The hole 50 which is adjacent the notch 44}contains an explosive 51 which is positioned by rotary movement of therotor to form a continuous passage through which the charge is ignited.The hole 52 is lined up with the hole in the bottom plate 8 when therotor is in safety position and held aligned by the ball 20, FIG. 1. Thethickness of the rotor and the diaphragm together is only slightlygreater than the diameter of the ball so that the ball may be completelyhoused in the rotor and diaphragm to permit free movement of the rotor.

The rotor housing in addition to the well 30 is formed with a radialslot 54 the sides of which are parallel and serve as guides for a slide56 supporting a pin 58. A coil spring 60 holds the pin 58 normally inengagement with the rotor and prevents the rotor from moving from thesafety position until the pin is withdrawn. The spring is supported by arod 62 which in turn is carried by the crossbar 64 mounted in the slot54.

Let it be assumed, by way of example, that the fuze is assembled in thesafety position with the hole in the bottom plate aligned with the hole52 of the rotor and the ball 20 firmly held by the retaining cup 16 andextending into the hole 52. When the missile is fired, the setback forcebreaks the ball loose from the retaining cup forcing the ends of the cupinto the flared portion 14 of the hole. The ball is thrown into thetapered hole 34 when it is subjected to the acceleration of the missile.It is held in the tapered hole until the acceleration value is zerowhich occurs when the missile is about eight feet from the gun and thenthe centrifugal force of the spinning missile urges the ball 20 intoclose engagement with the tapered wall of the hole 34, which directs itinto the hole 52 of the rotor. The centrifugal force has moved the slideon the rod 62 compressing the spring 60 and removing the pin 58 fromengagement with the rotor. With the moving of the ball 20 completelyinto the hole 52 the rotor will turn through approximately 90 moving thehole 50 into armed position, the turning of the rotor being limited byengagement of the shoulder 46 with the pin 48 and locked in position bythe strip 38 engaging the notch 62. The rotor is now locked in armedposition so that the missile may explode at the end of its flight. Thelead 41 on one side and the notch 40 on the other insure the turning ofthe rotor when the missile spins.

Obviously many modifications and variations of the present invention arepossible'in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. An arming delay mechanism for a spin type projectile of the typefired from a gun comprising a switch housing having a bottom plate, adisc shaped body attached to said plate and formed with an eccentriccircular well and a radial slot extending into said well, an armingrotor formed with a transverse circular opening and, carried in saidwell for limited angular movement, means carried within the radial slotand actuated by spin force set up by firing the projectile normallyholding the rotor in a safe position, means carried by the bottom plateand actuated by setback force, said disc being formed with a taperedhole partially receiving the means actuated by the setback force to holdthe rotor in said safe position after the arming rotor has been releasedby the spin actuated means until zero linear acceleration is reached,whereby centrifugal force generated by spin of the projectile will movethe setback actuated means from the tapered hole to a positionpermitting partial rotation of the rotor, and means for stopping therotor in an armed position.

2. An arming delay mechanism according to claim 1 including a rupturablecup carried by the switch housing plate for holding the means actuatedby setback force prior to the firing of the projectile.

3. An arming delay mechanism according to claim 2 wherein the meansactuated by the setback force is a ball.

4. An arming delay mechanism according to claim 3 including a diaphragmcarried between the rupturable cup and the eccentric circular wellcarried rotor formed with a arc cutout portion, the thickness of saiddiaphragm and said rotor being slightly greater than the diameter of theball to permit movement of the rotor with the ball extending through the90 arc cutout portion of said diaphragm, the diaphragm being so locatedas to position the arc to permit 90 movement of the rotor from safe toarmed position.

5. An arming delay mechanism according to claim 1 wherein the body has anotch communicating with the eccentric circular well, formed therein anda movable strip member slidea bly mounted in a diametric groove locatedin the face of the rotor carried by said eccentric circular well, saidstrip member being movable under centrifugal force to engage said notchto lock the rotor in armed position.

6. An arming delay mechanism according to claim 1 and including a chargeof explosive carried in a transverse hole in the rotor and positioned topresent a continuous passage thru which the charge is ignited when therotor is moved to armed position.

References Cited in the file of this patent UNITED STATES PATENTS

